1. Field of the Invention
The present invention deals with the field of attachment devices for securement to the runners of conventional sleds to facilitate use of such sleds on soft and/or deep snow surfaces. It has been found that when utilizing a sled upon such soft surfaces the narrow width of the standard runners thereof inhibit full and efficient usage of the sled itself.
The present invention provides a means for utilizing the attachment of a ski-like member to each of the runners of a conventional sled to overcome this problem. The present invention particularly claims a unique locking means for providing a secure fixed attachment between such ski members and the runners of the sled. This locking means provides a simple and efficient and easily maintained means of securing firm interlocking attachment yet still allowing the simple removal of the ski members whenever usage in soft or deep snow is not needed. The present device also utilizes a simple locking means for securing firm attachment between the upwardly curved front section of the conventional sled runner and the forward section of the ski members or device of the present invention.
2. Description of the Prior Art
The usage of ski-like members for attachment to the runners of sleds is generally known in the prior art as evidenced by the following U.S. Pat. Nos.: 954,377, issued to J. Bystrom on Apr. 5, 1910; 3,578,351, issued to R. A. McAtee on May 11, 1971; and 3,751,057, issued to R. A. Matthiessen on Aug. 7, 1973. The locking means of the present invention illustrates particular advantages in the simplicity and easy maintainability thereof when considered in respect to the above patents and other prior art. In particular in U.S. Pat. No. 954,377 the spring clasp or fastening device which secures attachment between the ski member and the sled runner does not have the structural strength or easy maintenance qualities of the locking means of the present invention. Sled runners are utilized under very rough and demanding conditions due to the high speed and rough ground over which these conventional sleds often travel. As such the relatively complicated interlocking method disclosed in the '377 patent would not achieve the desired advantages of the simple interlocking single block design of the present invention. When an apparatus is put to such demanding usage the simplicity of design and ease of maintenance is a primary factor for consideration.
In U.S. Pat. No. 3,578,351 the locking means between the ski member and the sled runner utilizes at least two locking screws 34 at each locking location. The present invention utilizes only a single threaded locking member and, as such, is easier to manufacture and most importantly easier to maintain and install whenever desired at a sledding location. The U.S. Pat. No. 3,751,057 utilizes an elongated strip of sheet metal which is bent to provide a base. This ski member is formed with ears 19 of the base standing above the runner to interlock thereabove. The present design utilizes a simple flat base member which does not include the concave downwardly facing surface but achieves the desired control thereof by notches in the undersurface of the base member. Again the present design has advantages over this construction due to the ease of maintenance and simplicity in construction as well as the reduced cost of manufacture. Another important advantage of the present design over each of these patents and all other prior art is the ability to easily and simply secure the ski sled attachment device of the present invention to sled runners of any length or contour. That ability is achieved by the flexibility of the forward section and by the vertically adjustable characteristic of the locking means.